1. Field of the Invention
The present invention relates generally to braking systems and arrangements for vehicles, such as trains and, in particular to a braking system for providing control and monitoring functions in a penalty brake arrangement for stopping the vehicle in specified situations or under specified conditions.
2. Description of the Related Art
In order to slow or stop a vehicle traversing a path, a braking system is employed. When used in connection with trains, trucks, subways, buses and other mass transit vehicles, these braking systems are often complex braking arrangements. Further, these arrangements often include certain fail-safe components or controls in order to ensure that the vehicle may be slowed or stopped in a variety of situations, e.g., equipment failure, control system failure, operator error or loss of vigilance, emergency conditions, etc. The portions that are used in these “emergency” or automated braking situations are often referred to as penalty braking systems or arrangements.
With specific reference to trains, and as is known in the art, in order to safely traverse a track in a track network, a train includes a complex braking arrangement situated over multiple cars for use in safely slowing and/or stopping the train in specified situations. Normally, the braking system on such trains is a pneumatically-driven arrangement having mechanisms and components that interact with each railroad car attached to the engine(s). For example, in one known braking arrangement for a train, an operator of the train has control over the braking arrangement through the use of an operator control valve. Through the movement of a lever associated with the control valve, the operator can adjust the amount of braking to be applied in the braking arrangement. The higher the braking force selected, the faster the braking arrangement will attempt to slow and stop the train. Compressed air is supplied through the control valve to a brake pipe that extends along and is associated with each railcar. Each car includes an arrangement that allows an auxiliary reservoir to be charged with air via a valve, as well as a brake cylinder that is in communication with the valve. The brake cylinder is operable to urge a brake shoe mechanism against a surface of the wheel, thus slowing or stopping the train.
While control over the braking arrangement by the operator is preferred and normally implemented, many braking systems utilize a brake interface in communication with a brake control component that permits automated, semi-automatic or penalty braking to occur. For example, in many automated train control systems, e.g., a Positive Train Control (PTC) system (e.g., the Electronic Train Management System (ETMS) of Wabtec), an Automated Train Control (ATC) system, etc., a brake interface (circuit) is in operable communication with the locomotive braking arrangement for the purpose of stopping the train in the event of an unsafe condition that may either exist at the current point in time (e.g., overspeed), or is predicted to exist in the future (e.g., violation of an upcoming authority limit). This brake interface is often considered a critical component of the overall braking system, and should preferably have some form of redundancy in order to meet the safety levels expected by the railroad industry and associated regulating bodies.
These train control systems can be used in connection with a variety of types of braking arrangements, such as the pneumatically-driven arrangement discussed above. Further a typical locomotive braking system that includes the brake interface (circuit) falls into one of two categories. The first type is an electronic braking system that requires an electrically-isolated voltage source driving a “vital” input on the electronic air brake computer or controller. In this arrangement, the brake control arrangement (or brake input), which is in communication with the braking arrangement, requires some voltage or current that holds the brakes from applying. If the input voltage drops to zero, the braking arrangement will apply at a full service rate and stop the train.
Another type of braking system includes a brake control arrangement in the form of a normally-open electrically-controlled pneumatic valve, commonly referred to as a “P2A” valve. This type of control arrangement is utilized in connection with traditional non-electronic air brake locomotives, and this arrangement operates in a manner similar to the electric input arrangement discussed above, where electrical current in the circuit closes the valve and holds the brakes from applying. In particular, if the voltage or current drops to zero, the pneumatic valve will open and the braking arrangement will apply and bring the train to a complete stop.
It is known in braking systems, and in particular to brake interfaces for locomotives, to supply power from a penalty power source through a circuit to a brake control arrangement (whether direct input in the electronics, or through the brake input in the from of an electrically-controlled pneumatic valve), which is in operational communication with the braking arrangement. As discussed above, when the voltage drops to zero at the control arrangement input, the brake control arrangement implements a full service rate application of the braking arrangement. Accordingly, such an arrangement is vital to the safe operation and control of the train (or any vehicle where such an arrangement is utilized).
Further, and in general, there exist different train control systems and methods for braking and/or controlling trains. For example, see U.S. Pat. Nos. 7,073,753 to Root et al.; 6,932,437 to Root et al.; 6,896,339 to Moffitt et al.; 6,746,087 to Reynolds et al.; 6,676,229 to Marra et al.; 6,648,422 to Root et al.; 6,375,276 to Delaruelle; 6,371,575 to Lewis et al.; 6,318,811 to Root et al.; 6,302,495 to Peltz; 6,126,247 to Paul et al.; 6,120,109 to Wood et al.; 5,862,048 to Knight; 5,817,934 to Skantar; 5,721,683 to Joyce, Jr. et al.; 4,692,867 to Poole; 4,626,039 to Worbois; 4,534,599 to Wright et al.; and 4,107,253 to Borg et al. Also, see Patent Publication Nos.: 2007/0063581 to Teifke et al.; 2007/0063578 to Reynolds et al.; 2006/0076826 to Kane; 2005/0173974 to Fuderer et al.; 2005/0099061 to Hollandsworth et al.; 2005/0085960 to Lumbis et al.; 2005/0027410 to Kanner et al.; 2004/0122566 to Horst et al.; 2004/0084957 to Root et al.; 2004/0006413 to Kane et al.; 2003/0009274 to Peterson, Jr. et al.; 2002/0153766 to Kettle, Jr.; and 2002/0147538 to Marra et al.
Therefore, there exist prior art electronic and/or pneumatic braking and control systems, however, such known systems exhibit various drawbacks and deficiencies in both development and implementation. For example, since brake interface systems (and braking arrangements in general) are vital to the safe operation of the vehicle, certain redundancies and checks to ensure proper, timely and effective operation of the braking arrangement in an emergency or other specified situation is of the utmost importance. Known prior art systems operate to implement a full service rate application of brakes when voltage or current in the brake control arrangement drops to zero. However, such systems do not include further controllable aspects, functions and components that provide additional, beneficial backup and insurance of proper brake application in certain situations. In addition, there remains a need in the art for functions and features that permit the brake interface (circuit) to be tested for appropriate operation, without actually implementing an emergency “stop” of the train. Still further, many of these prior art systems and methods are amenable to further augmentation or beneficial functioning in order to provide safer braking arrangements on mass transit vehicles, such as trains and the like. As one would expect, the safe operation of such vehicles is a necessity for protecting the operator, crew, motorists, pedestrians, etc.